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Web crawler

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Web crawler

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  1. Downloading defined:Downloading is the process of copying a file (such as a game or utility) from one computer to another across the internet. When you download a game from our web site, it means you are copying it from the author or publisher's web server to your own computer. This allows you to install and use the program on your own machine. • Here's how to download a file using Internet Explorer and Windows 98. If you're using a different browser such as Netscape Navigator or a different version of Windows, your screens may look a little different, but the same basic steps should work. • 1. Click on the download link for the program you want to download. • 2. You may be asked if you want to save the file or run it from its current location. If you are asked this question, select "Save." If not, don't worry -- some browsers will automatically choose "Save" for you.

  2. 3. You will then be asked to select the folder where you want to save the program or file, using a standard "Save As" dialog box. Pay attention to which folder you select before clicking the "Save" button. It may help you to create a folder like "C:\My Documents\Download" for all of your downloads, but you can use any folder you'd like. 4. The download will now begin. Your web browser will keep you updated on the progress of the download by showing a progress bar that fills up as you download. You will also be reminded where you're saving the file. The file will be saved as "C:\My Documents\Download" in the picture below. • Note: You may also see a check box labeled "Close this dialog box when download completes." If you see this check box, it helps to uncheck this box. You don't have to, but if you do, it will be easier to find the file after you download it.

  3. 5. Depending on which file you're downloading and how fast your connection is, it may take anywhere from a few seconds to a few minutes to download. When your download is finished, if you left the "Close this dialog box when download completes" option unchecked, you'll see a dialog box like this one:

  4. 6. Now click the "Open" button to run the file you just downloaded. If you don't see the "Download complete" dialog box, open the folder where you saved the file and double-click on the icon for the file there. • What happens next will depend on the type of file you downloaded. The files you'll download most often will end in one of two extensions. (An extension is the last few letters of the filename, after the period.) They are: • * .EXE files: The file you downloaded is a program. Follow the on-screen instructions from there to install the program to your computer and to learn how to run the program after it's installed.* .ZIP files: ZIP is a common file format used to compress and combine files to make them download more quickly. Some versions of Windows (XP and sometimes ME) can read ZIP files without extra software. Otherwise, you will need an unzipping program to read these ZIP files.

  5. Web crawler • A Web crawler is a computer program that browses the World Wide Web in a methodical, automated manner or in an orderly fashion. Other terms for Web crawlers are ants, automatic indexers, bots, Web spiders,Webrobots,Webscutters.

  6. A Search Engine Spider (also known as a crawler, Robot, SearchBot or simply a Bot) is a program that most search engines use to find what’s new on the Internet. Google’s web crawler is known as GoogleBot. There are many types of web spiders in use, but for now, we’re only interested in the Bot that actually “crawls” the web and collects documents to build a searchable index for the different search engines. The program starts at a website and follows every hyperlink on each page.

  7. Three Steps of Web Crawling • three steps that are involved in the web crawling procedure. First, the search bot starts by crawling the pages of your site. Then it continues indexing the words and content of the site, and finally it visit the links (web page addresses or URLs) that are found in your site. When the spider doesn’t find a page, it will eventually be deleted from the index. However, some of the spiders will check again for a second time to verify that the page really is offline.

  8. Web indexing • Web indexing (or Internet indexing) includes back-of-book-style indexes to individual websites or an intranet, and the creation of keyword metadata to provide a more useful vocabulary for Internet or onsite search engines. With the increase in the number of periodicals that have articles online, web indexing is also becoming important for periodical websites. • Back-of-the-book-style web indexes may be called "web site A-Z indexes". The implication with "A-Z" is that there is an alphabetical browse view or interface. This interface differs from that of a browse through layers of hierarchical categories (also known as a taxonomy) which are not necessarily alphabetical, but are also found on some web sites.

  9. Use of Boolean Search Operators • AND ( CA AND ICMA) • OR (CA or ICMA) • NOT (NOT CA) • “ ” ( “ SKANS School”) • - (Minus) excludes • + (Plus) Includes

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